Biomass Group, Nanjing Agricultural University, PO Box 68, 40 Dianjiangtai Road, Nanjing 210031

Comprehensive insights into synergistic effects of cotton stalk and polyethylene in hydrothermal liquefaction process

Recently, PhD student Mr. Sheng-ren Li, supervised by Prof. Zhen Fang, published a research article on hydrothermal synergistic effects of cotton straw and polyethylene.

The synergistic effects of cotton stalks (CS) and polyethylene (PE) during the hydrothermal co-liquefaction process increased the bio-oil yield by 22.8%, with solid residue decreased by 6.1% and {gas + aqueous} products declined by 18.2%. GC-MS presented oxygen-containing compounds in oil decreased but hydrocarbons (HCs from 6.2 % to 66.8%) increased. TG analysis and FT-IR of solid residues revealed significant mutual promotion of the decomposition between CS and PE. The decomposition kinetics calculation demonstrated that co-treatment reduced the decomposition temperature by 33 ℃, increased the mass loss by 7.8 wt%, and lowered the decomposition activation energy by 6.8 % (from 240.0 to 225.7 KJ/mol). Moreover, co-liquefaction of PE with biomass components further revealed that cellulose in CS predominantly facilitated the depolymerization of PE, followed by hemicellulose. This effect could be attributed to the acid from hydrolysis of cellulose and hemicellulose as well as high [H]⁺/[OH]^– concentration in from hydrothermal water, which promoted the β-scission of PE. The synergistic reaction pathways were proposed: CS and PE mutually promoting decomposition, with PE-derived olefins and hydrogen undergoing Diels-Alder, alkylation, and hydrodeoxygenation (HDO) reactions with CS intermediates, thereby enhancing HCs yield and inhibiting carbonization rearrangement of intermediates. This work reveals the causes and reaction pathways underlying synergistic effects, offering comprehensive guidance on producing crude bio-oil.

Related results were accepted in Chemical Engineering Journal：

SR Li, GQ Zhu, C He, LJ Xu*, JA Kozinski, Zhen Fang*, Comprehensive insights into synergistic effects of cotton stalk and polyethylene in hydrothermal liquefaction process, Chemical Engineering Journal, 502 (2024), 157845. https://doi.org/10.1016/j.cej.2024.157845

Cellulose and hemicellulose predominantly facilitate the β-scission of PE, with the  derived hydrogens and olefins undergoing Diels-Alder, alkylation, and HDO reactions with lignocellulosic intermediates. (纤维素和半纤维素主要促进PE的β-scission,其衍生的氢和烯烃与木质纤维素中间体发生Diels-Alder 、烷基化和HDO反应) 。

棉花秸秆和聚乙烯在水热液化过程中协同效应的综合研究

近期，博士生李胜任在方真教授的指导下，在国际学术期刊Chemical Engineering Journal发表了一篇关于棉花秸秆与聚乙烯水热协同效应的研究性论文。

棉花秸秆(CS)和聚乙烯(PE)在水热共液化过程中的协同作用将生物油产率提高了22.8%，固体残渣减少了6.1 %，气+水产物减少了19.2%。气相色谱-质谱联用（GC-MS）分析表明，油中含氧化合物含量下降，而碳氢化合物(HC)含量从6.2%上升至66.8%。固体残留物的热重（TG）分析和傅里叶变换红外光谱（FT-IR）分析表明，CS和PE之间存在显著的相互促进作用。分解动力学计算表明，共处理使分解温度降低了33℃，质量损失增加了7.8 wt%，分解活化能降低了6.8%（从240.0降至225.7 KJ/mol）。此外，PE与生物质组分的共液化进一步表明，CS中的纤维素主要促进PE的解聚，其次是半纤维素。这可能是由于纤维素和半纤维素水解产生的酸以及热液中较高的[H]⁺/[OH]^–浓度促进了PE的β-scission。提出了CS和PE的协同反应途径：CS和PE相互促进分解，PE衍生烯烃和氢与CS中间体发生Diels-Alder、烷基化和加氢脱氧（HDO）反应，从而提高HC产率，抑制中间体的碳化重排。这项工作揭示了引发协同效应的原因和反应途径，为生物原油生产提供了综合指导。

结果发表在Chemical Engineering Journal：

SR Li, GQ Zhu, C He, LJ Xu*, JA Kozinski, Zhen Fang*, Comprehensive insights into synergistic effects of cotton stalk and polyethylene in hydrothermal liquefaction process, Chemical Engineering Journal, 502 (2024), 157845. https://doi.org/10.1016/j.cej.2024.157845

Regulating N-doped biochar with Fe-Mo heterojunctions as cathode in long-life zinc-air battery

Recently, PhD student Miss Xiao-ru Meng, supervised by Dr. Shuai Gao and Prof. Zhen Fang, published a research article on synthesizing cathode from soybean straw for zinc-air battery.

Carbonaceous electrode loaded nano Mo₂C-Fe₃N@NCF was synthesized by solvothermal and pyrolysis from soybean straw for high-performance zinc-air batteries (ZABs). The empowered ZAB achieved 1.51 V open-circuit voltage, 88.40 mW cm⁻² power density and over 1150 h cycle life. Density functional theory analysis indicates that charge transfer from Mo₂C-Fe₃N heterogeneous structure to N-doped biochar can significantly reduce the reaction barrier for oxygen reduction/evolution reactions, enhancing the adsorption of oxygen intermediates. Cellulose-derived carbon provides a large specific surface area, and N-doping enhances the conductivity of the resultant biochar, which both play a crucial role in the efficient loading of Fe and Mo active sites. This work inspires the design and application of interfacial engineering on low-cost biochar carriers.

Related results were published in Chemical Engineering Journal:

XR Meng, S Gao*, NX Liu, PD Wu, Zhen Fang*. Regulating N-doped biochar with Fe-Mo heterojunctions as cathode in long-life zinc-air battery, Chemical Engineering Journal, 500 (2024), 157463. https://doi.org/10.1016/j.cej.2024.157463

 Carbonaceous material with multilayer structure derived from soybean straw was developed for long-life zinc-air batteries一种由大豆秸秆衍生的多层结构碳质材料，用于长寿命锌空气电池。

以Fe-Mo异质结为阴极调控长寿命锌空气电池中的 N 掺杂生物炭

近期，博士生孟晓茹同学在高帅博士和方真教授的指导下，在国际学术期刊Chemical Engineering Journal发表了一篇关于生物炭制备高性能氧电催化剂的研究性论文。

碳质电极负载纳米Mo₂C-Fe ₃N@NCF 是通过大豆秸秆的溶剂热和热解合成的，用于高性能锌空气电池（ZABs）。可逆的ZAB实现了1.51 V开路电压，88.40 mW cm⁻²功率密度和超过1150小时的循环寿命。密度泛函理论分析表明，从Mo₂C-Fe₃N向N掺杂生物炭发生电荷转移，此非均相结构可以显著降低氧还原/析出反应的反应势垒，增强氧中间体的吸附。纤维素衍生的碳提供了较大的比表面积，而N掺杂增强了所得生物炭的电导率，这两者都在Fe和Mo活性位点的有效负载中起着至关重要的作用。这项工作启发了界面工程在低成本生物炭载体上的设计和应用。

结果发表在Chemical Engineering Journal:

XR Meng, S Gao*, NX Liu, PD Wu, Zhen Fang*, Regulating N-doped biochar with Fe-Mo heterojunctions as cathode in long-life zinc-air battery, Chemical Engineering Journal, 500 (2024), 157463. https://doi.org/10.1016/j.cej.2024.157463

Dual lipases immobilized on magnetic hydrophobic biochar for one-step production of biodiesel in deep eutectic solvent

Recently, PhD student Miss Jing-jing Guo supervised by Prof. Zhen Fang published a research article in Fuel about biodiesel production from high acid value oil with immobilized dual lipases.

Magnetic hydrophobic biochar was synthesized via pyrolysis of the chelated carboxymethyl cellulose/Fe³⁺ and modification by composite silanes, and subsequently used to covalently/physically immobilize dual lipases CALB/ET. The activity of dual lipases immobilized on hydrophobic magnetic biochar (16.1 U/mg) was increased by 11.8% than magnetic biochar, or 3.9% and 8.1% higher than that of single immobilized lipase ET (15.5 U/mg) and immobilized lipase CALB (14.9 U/mg), respectively. The highest loading of 39.5 mg lipase/g support was obtained with 17.9 U/mg activity. The immobilized dual lipases were stable with relative activity of 92.6% and 95.4% at 50 °C and pH 9 vs. 74.6% and 83.9% for liquid dual lipases, respectively. The immobilized dual lipases were further used for one-step production of biodiesel from acid oil (acid value 38 mg KOH/g) in deep eutectic solvent at 97.9% yield with 5 cycles (75.2%). Enzymatic reactions promote biodiesel purification, and crude biodiesel had 0.27 mg KOH/g acid value and 0.015% glycerol that met both Chinese national and US ASTM standards. The activation energy was 41.2 kJ/mol with kinetic Michaelis constant of 7.92×10^-1 mol/L. The immobilized dual lipases for one-step production and purification of biodiesel presented excellent activity that provided a new insight for the development of novel immobilized lipase in biodiesel production.

Related results were published in Fuel:

Jing-jing Guo, Li Wang, Yi-tong Wang, Wo-na Ding, Wei-wei Liu, Zhen Fang*. Dual lipases immobilized on magnetic hydrophobic biochar for one-step production of biodiesel in deep eutectic solvent. Fuel (IF 6.7), 381 (2025), 133497. https://doi.org/10.1016/j.fuel.2024.133497

Two lipases were successfully covalent/physical immobilized on magnetic hydrophobic biochar for direct production of biodiesel at 97.9% yield from acid oil at low temperature of 35 °C. （双脂肪酶成功共价/物理固定化在磁性疏水生物炭上并用于在35 °C低温下催化酸性油制备生物柴油，产率为97.9%）。

磁性疏水生物炭固定化双脂肪酶在低共熔溶剂中一步法生产生物柴油

近期，博士生郭静静同学在方真教授的指导下，在国际学术期刊Fuel（Q1，IF 6.7）发表了一篇关于固定化双脂肪酶催化高酸值油制备生物柴油的研究性论文。

通过热解羧甲基纤维素/Fe³⁺螯合物和复合硅烷的改性制备了磁性疏水生物炭，并用于共价/物理固定化双脂肪酶CALB/ET。双脂肪酶固定化在疏水磁性生物炭上的活性（16.1 U/mg）比其固定化在磁性生物炭上提高了11.8%。固定化双脂肪酶CALB/ET的活性比固定化脂肪酶ET（15.5 U/mg）和固定化脂肪酶CALB（14.9 U/mg）分别提高了3.9%和8.1%。最高酶载量为39.5 mg脂肪酶/g载体，酶活为17.9 U/mg。在50 °C和pH 9时，固定化双脂肪酶的相对酶活分别为92.6%和95.4%，而液体双脂肪酶的相对酶活为74.6%和83.9%。在低共熔溶剂体系中，固定化双脂肪酶用于催化酸性油（酸值38 mg KOH/g）一步法制备生物柴油，产率为97.9%。固定化双脂肪酶循环5次，生物柴油产率仍为75.2%。该反应体系促进了生物柴油的纯化，粗生物柴油的酸值为0.27 mg KOH/g，甘油含量为0.015%，符合中国和美国ASTM的标准。动力学研究表明该反应的活化能为41.2 kJ/mol，动力学米氏常数为7.92×10^-1 mol/L。固定化双脂肪酶在一步法生产和纯化生物柴油中表现出优异的活性，为生物柴油生产中新型固定化脂肪酶的开发提供了新的见解。

结果发表在Fuel:

Jing-jing Guo, Li Wang, Yi-tong Wang, Wo-na Ding, Wei-wei Liu, Zhen Fang*. Dual lipases immobilized on magnetic hydrophobic biochar for one-step production of biodiesel in deep eutectic solvent. Fuel (IF 6.7), 381 (2025), 133497. https://doi.org/10.1016/j.fuel.2024.133497

On Sep. 30, 2024, Prof. Zhen Fang was invited to the Celebration of the 75th Anniversary of the Founding of the PRC in Nanjing.

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Co-production of porous N-doped biochar and hydrogen-rich gas production from simultaneous pyrolysis-activation-nitrogen doping of biomass: Synergistic mechanism of KOH and NH₃

Recently, Master student Miss Yu-rou Wang supervised by Dr. Wei Chen and Prof. Zhen Fang published a research article entitled “Co-production of porous N-doped biochar and hydrogen-rich gas production from simultaneous pyrolysis-activation-nitrogen doping of biomass: Synergistic mechanism of KOH and NH₃” in Renewable Energy.

In this study, a method of simultaneous activation and nitrogen doping during biomass fast pyrolysis for co-production of porous N-doped biochar and H₂-rich gas production was proposed. The effect of temperature on chemical interaction mechanism of KOH and NH₃ was investigated at 500-800°C. Results showed that KOH and NH₃ had a synergistic effect on pore development and nitrogen doping, and the specific surface area and nitrogen content reached maximum values of 2008.37 m²/g and 5.05 wt%, respectively. It may be due to that NH₃ entered pores generating by KOH activation for further activation, and at the same time, excessive NH₃ could convert new O-containing groups to N-containing groups for more effective nitrogen doping. What’s more, the H₂ concentration and yield were up to 56.67 vol% and 517.95 mL/g, respectively. It indicates that the synchronization method of fast pyrolysis-activation-nitrogen doping is a promising approach, which is of great significance for the high-value utilization of biomass.

Related results were accepted in Renewable Energy：

120777. Y. Wang, W. Guo, W. Chen*, G. Xu, G. Zhu, G. Xie, L. Xu, C. Dong, S. Gao, Y. Chen, H. Yang, H. Chen, Zhen Fang, Co-production of porous N-doped biochar and hydrogen-rich gas production from simultaneous pyrolysis-activation-nitrogen doping of biomass: Synergistic mechanism of KOH and NH₃, Renewable Energy 229 (2024) 120777. https://doi.org/10.1016/j.renene.2024.120777.

Co-production of porous N-doped biochar and hydrogen-rich gas production from simultaneous activation and nitrogen doping during biomass fast pyrolysis 生物质快速热解过程中同步活化掺氮联产多孔掺氮炭和富氢气体

生物质同步热解-活化-掺氮联产多孔掺氮炭和富氢气体：KOH和NH₃的协同机制

最近，硕士生王雨柔在陈伟副教授和方真教授的指导下，在国际学术期刊Renewable Energy (Q1, IF = 8.7) 发表了一篇题为“Co-production of porous N-doped biochar and hydrogen-rich gas production from simultaneous pyrolysis-activation-nitrogen doping of biomass: Synergistic mechanism of KOH and NH₃”的研究性论文。

本研究提出了一种在生物质快速热解过程中同步活化掺氮的方法，可以实现多孔掺氮生物炭和富氢气体的联产。探究了温度（500-800°C）对 KOH 和 NH₃ 化学协同作用的影响。结果表明，KOH 和 NH₃ 对孔隙发育和氮掺杂有协同促进作用，比表面积和氮含量分别达到最大值 2008.37 m²/g 和 5.05 wt%。这可能是由于 NH₃ 进入 KOH 活化产生的孔隙进一步活化，同时过量的 NH₃ 可以将新生成的含氧官能团转化为含氮官能团，从而实现更有效地掺氮。此外，热解气体中氢气浓度和产量可达到 56.67 vol% 和 517.95 mL/g。这表明，同步快速热解-活化-掺氮的方法前景广阔，对生物质的高值化利用具有重要意义。

结果发表在Renewable Energy：

120777. Y. Wang, W. Guo, W. Chen*, G. Xu, G. Zhu, G. Xie, L. Xu, C. Dong, S. Gao, Y. Chen, H. Yang, H. Chen, Zhen Fang, Co-production of porous N-doped biochar and hydrogen-rich gas production from simultaneous pyrolysis-activation-nitrogen doping of biomass: Synergistic mechanism of KOH and NH₃, Renewable Energy 229 (2024) 120777. https://doi.org/10.1016/j.renene.2024.120777.